Non-volatile memory express (NVMe) and NVMe over fabrics (NVMeoF) (or NVMf in short) are new emerging technologies. NVMe is a standard that defines a register-level interface for host software to communicate with a non-volatile memory subsystem (e.g., a solid-state drive (SSD)) over a peripheral component interconnect express (PCIe) bus.
NVMeoF defines a common architecture that supports an NVMe block storage protocol over a wide range of storage networking fabrics such as Ethernet, Fibre Channel, InfiniBand, and other network fabrics. For an NVMeoF-based system, an X86-based central processing unit (CPU) on a motherboard is no longer required to move data between an initiator (e.g., host software) and a target device (i.e., an NVMeoF device) because the target device is capable of moving data by itself. The term “fabric” represents a network topology in which network nodes can pass data to each other through a variety of interconnecting protocols, ports, and switches. For example, Ethernet-attached SSDs may attach directly to a fabric, and in this case the fabric is the Ethernet.
Today's Ethernet switch boards are designed to accommodate Ethernet-attached SSDs have a high port count because a single switch controller with a high port count would bring the average cost-per-port down. For example, an Ethernet switch can commonly have 128 ports for 25G Ethernet switching. A typical Ethernet SSD rack chassis can consume only 24-48 ports of the 128 ports that are available for the Ethernet switch leaving the remaining 80-104 ports unused. In addition, the mounting of all the available 128 ports is physically impossible due to the spatial limitation of a 2U panel of the Ethernet SSD rack chassis. In these cases, using an Ethernet switch with an excessive number of ports in each Ethernet SSD rack chassis would be wasteful and costly. Mounting of the 128 ports to the chassis may be possible, but it would not be a viable solution in that it requires more rack space and a redesign of the system architecture including the chassis and/or the rack-mounted system as well as the connectors of the attached SSDs.